A critical research area cited in the Tox21 Phase 3 strategic plan is incorporation of genetic diversity in in vitro screening strategies to determine population dynamics in chemical response. This study leverages lysates collected from Diversity Outbred mouse neural progenitor cells exposed to 3 potentially neurotoxic agents at 12 chemical concentrations. In the course of this analysis, we will determine (1) key transcriptional pathways that distinguish susceptible from nonsusceptible mouse lines for each chemical, (2) points of departure for key molecular events as defined by transcriptional status, and (3) toxicodynamic variability factors that describe interindividual differences in chemical response within the Diversity Outbred (DO) mouse population.